/**
 * Copyright 2009-2020 the original author or authors.
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.ibatis.logging;

import java.lang.reflect.Constructor;

/**
 * @author Clinton Begin
 * @author Eduardo Macarron
 */
public final class LogFactory {

	/**
	 * Marker to be used by logging implementations that support markers.
	 */
	public static final String MARKER = "MYBATIS";

	private static Constructor<? extends Log> logConstructor;

	static {
		//此处创建日志实现
		tryImplementation(LogFactory::useSlf4jLogging);
		tryImplementation(LogFactory::useCommonsLogging);
		tryImplementation(LogFactory::useLog4J2Logging);
		tryImplementation(LogFactory::useLog4JLogging);
		tryImplementation(LogFactory::useJdkLogging);
		tryImplementation(LogFactory::useNoLogging);
	}

	private LogFactory() {
		// disable construction
	}

	public static Log getLog(Class<?> clazz) {
		return getLog(clazz.getName());
	}

	public static Log getLog(String logger) {
		try {
			return logConstructor.newInstance(logger);
		} catch (Throwable t) {
			throw new LogException("Error creating logger for logger " + logger + ".  Cause: " + t, t);
		}
	}

	public static synchronized void useCustomLogging(Class<? extends Log> clazz) {
		setImplementation(clazz);
	}

	public static synchronized void useSlf4jLogging() {
		setImplementation(org.apache.ibatis.logging.slf4j.Slf4jImpl.class);
	}

	public static synchronized void useCommonsLogging() {
		setImplementation(org.apache.ibatis.logging.commons.JakartaCommonsLoggingImpl.class);
	}

	public static synchronized void useLog4JLogging() {
		setImplementation(org.apache.ibatis.logging.log4j.Log4jImpl.class);
	}

	public static synchronized void useLog4J2Logging() {
		setImplementation(org.apache.ibatis.logging.log4j2.Log4j2Impl.class);
	}

	public static synchronized void useJdkLogging() {
		setImplementation(org.apache.ibatis.logging.jdk14.Jdk14LoggingImpl.class);
	}

	public static synchronized void useStdOutLogging() {
		setImplementation(org.apache.ibatis.logging.stdout.StdOutImpl.class);
	}

	public static synchronized void useNoLogging() {
		setImplementation(org.apache.ibatis.logging.nologging.NoLoggingImpl.class);
	}

	private static void tryImplementation(Runnable runnable) {
		if (logConstructor == null) {
			try {
				runnable.run();
			} catch (Throwable t) {
				// ignore
			}
		}
	}

	private static void setImplementation(Class<? extends Log> implClass) {
		try {
			Constructor<? extends Log> candidate = implClass.getConstructor(String.class);
			Log log = candidate.newInstance(LogFactory.class.getName());
			if (log.isDebugEnabled()) {
				log.debug("Logging initialized using '" + implClass + "' adapter.");
			}
			logConstructor = candidate;
		} catch (Throwable t) {
			throw new LogException("Error setting Log implementation.  Cause: " + t, t);
		}
	}

}
